A unit process is the smallest building block in a life cycle model. Each unit process contains qualified input and output data including resource requirements and emissions. The NETL Unit Process Library is available to increase the public's understanding of the tools used to inform energy policy and guide energy research.

Each NETL unit process contains a DS and DF file. The DS file (Detailed Spreadsheet Documentation) is an Excel file that contains all of the parameters, inputs, and outputs for a given system as well as background data, calculations and quality scores. The DF file (Process Documentation File) is a PDF document that contains major assumptions and data sources that are the basis for each unit process.